Interconnect system and methods of installing the same

ABSTRACT

An interconnect system is provided that involves pre-installing a connector housing an optical connector in an adapter and a ferrule of the same optical connector on a cable. The ferrule terminates one or more groups of optical fibers, and a ferrule push component is also pre-installed on the same group(s) of optical fibers. The connector housing is configured to receive and retain the ferrule and ferrule push component without being removed from the adapter to simultaneously form the optical connector and install the optical connector in the adapter. Embodiments such an interconnect system involving high fiber-count cables and related installation methods involving many optical connections are disclosed.

PRIORITY APPLICATION

This application is a continuation of U.S. application Ser. No.17/227,750, filed on Apr. 12, 2021, which claims the benefit of priorityto U.S. Application No. 63/010,216, filed on Apr. 15, 2020, the contentof which is relied upon and incorporated herein by reference in itsentirety.

BACKGROUND

This disclosure relates generally to optical connectivity, and moreparticularly to an interconnect system and related methods that involvepre-installing at least one component of an optical connector in anadapter and another component of the same optical connector on a cable.

Large amounts of data and other information transmitted over theinternet has led businesses and other organizations to develop largescale data centers for organizing, processing, storing, and/ordisseminating large amounts of data. Data centers contain a wide rangeof IT and other communication equipment including, for example, servers,networking switches, routers, storage subsystems, etc. Data centersfurther include a large amount of cabling and equipment racks toorganize and interconnect the communication equipment in the datacenter. For example, optical fiber cables and rack-mounted hardware tosupport optical connections are used extensively in data centers.Optical fibers can support very high bandwidths with lower signal losscompared to traditional data transmission mediums (e.g., copper wires).

The connections between communication equipment in large-scale datacenters is typically not confined to a single building. Many modern datacenters include multi-building campuses having, for example, one primaryor main building and a number of auxiliary buildings in close proximityto the main building. All the buildings on the campus are interconnectedby a local fiber optic network. More particularly, each of the auxiliarybuildings are typically connected to the main building by one or morehigh fiber-count optical cables referred to as “trunk cables”. Eachtrunk cable may include thousands of optical fibers. Indeed, fibercounts of 3,456 or higher are now common.

To provide optical connectivity within a building, the optical fibers ofa trunk cable are typically spliced to optical fibers of indoordistribution cables. The splices may be stored and organized in a splicecabinet from which the indoor distribution cables extends. Morespecifically, the splice cabinet holds numerous splice trays that eachreceives a group of optical fibers from the trunk cable that have beenspliced to a group of optical fibers associated with the indoordistribution cables. Fusion splicing is commonly used as the primarytechnique for splicing the two groups of optical fibers together beforethe splices are stored and organized in the splice trays. The indoordistribution cables exit the splice cabinet and extend to desiredlocations within the building, such as to designated rows of equipmentracks. Connections to the IT equipment in the equipment racks areultimately made by the indoor distribution cables or cables that arepart of a structured cabling system for the building.

The amount of labor and time for connecting a trunk cable to the ITequipment in the main building on the data center campus is significant.In a typical installation process, it may take two techniciansapproximately two-weeks of time to fusion splice the optical fibers of atrunk cable to corresponding internal optical fibers of the mainbuilding. Additionally, fusion splicing is a labor-intensive method forconnecting optical fibers that is typically performed under fieldconditions, as opposed to under more highly controlled factoryconditions. Thus, the quality of the splicing and the attenuation of theoptical signal through the splice may vary widely depending on the fieldtechnicians' skill and experience.

SUMMARY

Embodiments of interconnect systems are provided in this disclosure, andparticularly interconnect systems that may be used in environments wherea large number of optical connections is needed and where there arecompeting demands for space, such as in hyperscale data centers.

According to one embodiment, an interconnect system comprises a cableassembly and at least one adapter panel for managing interconnections.The cable assembly includes: a cable jacket; different groups of opticalfibers carried within the cable jacket and extending beyond an end ofthe cable jacket; a plurality of ferrules each terminating one or morerespective groups of the different groups of optical fibers; and aplurality of ferrule push components corresponding to the plurality offerrules. Each ferrule push component of the plurality of ferrule pushcomponents is installed on the one or more respective groups of theoptical fibers that are terminated by the corresponding ferrule. Eachadapter panel of the at least one adapter panel includes a plurality ofadapters. The interconnect system further comprises a plurality ofconnector housings each coupled to a respective adapter of the pluralityof adapters independently from the cable assembly (i.e., without beingpart of the cable assembly when coupled to the respective adapter). Theplurality of connector housings are configured to receive and retain theplurality of ferrules and the plurality of ferrule push componentswithout being removed from the plurality of adapters.

Many embodiments are possible. Each ferrule of the plurality of ferrulesmay terminate a single group of the different groups of optical fibers,or each ferrule may terminate multiple groups of the different groups ofoptical fibers. Each group of the different groups of optical fibers maycomprise an optical fiber ribbon, or each group of the different groupsof optical fibers may include the respective optical fibers in anon-ribbon form.

In some embodiments, each ferrule of the plurality of ferrules includesa front end that defines an end face where the respective one or moregroups of the different groups of optical fibers terminate, a back endopposite the front end, and a shoulder between the front end and theback end that defines a maximum height and a maximum width of theferrule in a cross-sectional plane perpendicular to a longitudinal axisof the ferrule. Each ferrule push component of the plurality of ferrulepush components has a maximum height and maximum width in across-sectional plane perpendicular to a longitudinal axis of theferrule push that is substantially the same or less than the maximumheight and maximum width of the corresponding ferrule.

In some embodiments, for each adapter panel of the at least one adapterpanel, the plurality of adapters are arranged in a plurality of adapterrows, a plurality of adapter columns, or both a plurality of adapterrows and a plurality of adapter columns. The adapter panels may belocated on a frame, tray, or other support member.

In some embodiments, the pre-terminated cable assembly furthercomprises: a plurality of subunits within the cable jacket, wherein eachsubunit includes several of the different groups of optical fibers andseveral of the ferrules, and wherein each row of the plurality ofadapter rows or each column of the plurality of adapter columns includesa sufficient number of the adapters to correspond to the ferrulesassociated with any of the subunits. There may be a plurality of adapterpanels for the plurality of subunits.

In some embodiments, the interconnect system further comprises a cabinetthat includes a plurality of walls defining an interior volume. Eachadapter panel of the at least one adapter panel has a storage positionwithin the interior volume and is movable relative to the plurality ofwalls to a position at least partially outside the interior volume.

Methods of installing interconnect systems like the ones summarizedabove are also disclosed. According to one embodiment, such a methodcomprises: routing an end of the pre-terminated cable assembly thatincludes the plurality of ferrules from a remote location toward the atleast one adapter panel; and installing the plurality of ferrules in theplurality of adapters by inserting the plurality of ferrule pushcomponents into the plurality of connector housings. The plurality ofconnector housings are coupled to the plurality of adapters before theinstalling step and remain coupled to the plurality of adapters duringthe installing step.

In some embodiments, the installing step results in the plurality offerrules and the plurality of connector housings being coupled togetherto define a corresponding plurality of optical connectors that areinstalled in the plurality of adapters. The installing step may beperformed without any tools, and wherein once the installing step iscomplete, the plurality of optical connectors are removable from theplurality of adapters without any tools.

In some embodiments, the routing step further comprises pulling thepre-terminated cable assembly through a duct using a pulling gripassembly that covers the plurality of ferrules and the plurality offerrule push components. The routing step may also comprise routing theend of the pre-terminated assembly into a cabinet that includes the atleast one adapter panel and thereafter removing the pulling grip toexpose the plurality of ferrules, the plurality of ferrule pushcomponents, and portions of the different groups of optical fibers.Additionally, in some embodiments, the pulling grip is removed from theend of the pre-terminated cable assembly without a tool.

Additional features and advantages will be set out in the descriptionthat follows, and in part will be readily apparent to those skilled inthe technical field of optical connectivity.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding, and are incorporated in and constitute a part of thisspecification. The drawings illustrate one or more embodiment(s) and,together with the description, serve to explain principles and operationof this disclosure. Features and attributes associated with any of theembodiments shown or described may be applied to other embodimentsshown, described, or appreciated based on this disclosure.

FIG. 1 is an exploded perspective view of one example of an adapterassembly and one example of a pre-terminated sub-assembly according tothis disclosure, wherein the adapter assembly includes an MPO adapterand a connector housing pre-installed in the MPO adapter, and whereinthe pre-terminated sub-assembly includes a ferrule and a ferrule pushcomponent.

FIG. 1A is a perspective view of the connector housing of FIG. 1 inisolation.

FIG. 2 is a perspective view showing the ferrule push of FIG. 1 beingused to insert the ferrule into the connector housing that ispre-installed in the MPO adapter.

FIG. 3 is a perspective view showing the ferrule push of FIG. 1 fullyinserted into the connector housing to form an optical connector that iscoupled to the adapter.

FIG. 4 is a schematic view of a data center campus interconnectedaccording to an exemplary embodiment of this disclosure.

FIG. 5 is a cross-sectional view of one example of a trunk cable used inthe data center campus of FIG. 4 to interconnect buildings.

FIG. 6 is a cross-sectional view of one example of an indoor cable usedwithin buildings of the data center campus shown in FIG. 4 .

FIG. 7 is a schematic view of an end portion of the trunk cable of FIG.5 having subunits pre-terminated with ferrules.

FIG. 8 is a close-up schematic view of the ferrules associated with twoof the subunits in FIG. 7 .

FIG. 9 is an exploded perspective view of the pre-terminatedsub-assembly shown in FIG. 1 and a dust cap for that pre-terminatedsub-assembly.

FIG. 10 is a perspective view similar to FIG. 9 , but illustrates theferrule and the ferrule push of the pre-terminated sub-assembly in anassembled form; the dust cap remains spaced from these components.

FIG. 11 is a perspective view similar to FIG. 10 , but illustrates thedust cap installed on the ferrule and the ferrule push.

FIG. 11A is a schematic cross-sectional view of a portion of the dustcap and the ferrule push to illustrate features to assist with travel ofthe dust cap over the ferrule push.

FIG. 12 is a perspective of the trunk cable of FIG. 5 stored on a cablereel and a pulling grip assembly (“pulling grip”) covering an endportion of the trunk cable that includes pre-terminated sub-assemblies.

FIG. 13 is a perspective view of one example of a distribution cabinetused in the data center campus of FIG. 4 .

FIG. 14 is a perspective view of one example of a tray that is used tostore optical connections in the distribution cabinet of FIG. 13 ,wherein the tray includes adapter assemblies like what is shown in FIGS.1-3 .

FIG. 15 is a perspective view of one pre-terminated sub-assembly withthe dust cap (similar to FIG. 10 ) and an adapter assembly (similar toFIG. 1 ) intended to be coupled together during installation of aninterconnect system, wherein the adapter assembly includes a dust coverpre-installed in the connector housing of the adapter assembly.

FIG. 16 is a perspective view similar to FIG. 15 , but shows the dustcover removed from the connector housing.

DETAILED DESCRIPTION

Various embodiments will be clarified by examples in the descriptionbelow. In general, the description relates to an interconnect system fora building that involves a fiber optic cable being pre-terminated withsome components of optical connectors and at least one adapter panelhaving adapters pre-populated (i.e., pre-installed) with othercomponents of those optical connectors. The components terminating thecable and the components pre-installed on the adapters can be combinedduring installation of the interconnect system to result in functionableoptical connectors populating the adapter panel(s). The combining canoccur without removing the components that are pre-installed on theadapters.

It will be apparent based on the description below that the presentdisclosure is more than a mere disaggregation of known components forlater assembly. In other words, the present disclosure is not merelyabout taking known components of an optical connector that are normallyassembled together in one location to terminate a fiber optic cable, andthen separating them into two groups—one for installation on the cableat a first location, and another for installation on the cable at asecond location. This disclosure instead takes advantage of newcomponent designs that allow partial installation of an opticalconnector on a cable and partial installation of the same opticalconnector in an adapter. Complete installation of the optical connectoron the cable and complete installation of the optical connector in theadapter take place simultaneously (i.e., both are completed at the sametime). Thus, by the time the cable is terminated with the final opticalconnector, the optical connector is also installed in an adapter (e.g.,of an adapter panel) and ready for mating with a complementary opticalconnector that may be received on an opposite side of the adapter.

The basic concept is shown in FIGS. 1-3 , which illustrate an exampleinvolving components of a multi-fiber push-on/pull-off (MPO) opticalconnector (e.g., some according to IEC 61754-7-2: 2019 or TIA/EIA604-5-F: 2019; see FIG. 3 ). A brief overview of the concept is providedhere to facilitate discussion; additional details will be provided laterin this disclosure. Optical fibers are not shown in FIGS. 1-3 tosimplify the figures and this introductory discussion.

In general, optical connectors are designed to provide two primaryfunctions: alignment of optical fibers for optical coupling, andmechanical retention to maintain that alignment. In an MPO connector andmany other plug-type connectors, the primary component for the purposeof alignment is a ferrule. To this end, FIG. 1 illustrates a ferrule 52that may be installed on the ends of optical fibers to terminate theoptical fibers. The ferrule 52 is an MT-type ferrule having boresdesigned to receive and support optical fibers in a row or array (morethan one row). The optical fibers are secured to the ferrule 52 (e.g.,using an adhesive) and are processed so that their ends aresubstantially flush with an end face 54 of the ferrule 52, which may ormay not be angled relative to a plane that is perpendicular to alongitudinal axis of the ferrule 52. In this case, the presence of theguide pins 56 makes the ferrules male type ferrules, although thisdisclosure applies equally to female-type ferrules without guide pins.FIG. 1 also illustrates guide pins 56 protruding through the ferrule 52and a ferrule push component 58 (or “ferrule push 58”) located behindthe ferrule 52. Both of these components may also be installed on theoptical fibers that are terminated by the ferrule 52. Although the useof the guide pins 56 is well-known, the design and use of the ferrulepush 58 is not. This component is what will primarily be described infurther detail later in this Detailed Description section.

In an MPO connector and many other plug-type connectors, the primarycomponent for the purpose of retention is a connector housing (alsoreferred to simply as a “housing”, or as “connector body” or simply“body”). The housing receives the ferrule and includes a couplingmechanism, such as a latch feature for cooperating with a complementarylatching feature of an adapter. In FIG. 1 , a connector housing 62 of anMPO connector is shown as being pre-installed in an adapter 60 (also ofthe MPO-type, e.g. according to IEC 61754-7 or TIA/EIA 604-5) to form anadapter assembly 64. Although it cannot be seen it FIG. 1 , theconnector housing 62 is engaged by structure of the adapter 60 so as tobe retained. FIG. 1A illustrates the connector housing 62 in isolationto better appreciate this aspect. The connector housing 62 includeslatch recesses 66 (or “latch windows”) on opposite sides that areengaged by adapter latch arms (not shown) of the adapter 60 when theconnector housing 62 is installed in the adapter 60. The latch recesses66 (or more specifically, portions of the latch recesses 66) define amechanical reference datum upon which dimensions of the connectorhousing 62 can be consistently based for intermatability purposes. Thesame is true for the adapter latch arms. By defining certain dimensionof the adapter 60 and the connector housing 62 based on their respectivemechanical reference datums in a consistent manner, the associatedoptical connector 50 (FIG. 3 ; ferrule 52+connector housing 62, asdiscussed below) can mechanically intermate with other MPO-type opticalconnectors.

The structure of the connector housing 62 that has been described andthat is shown in FIG. 1A, namely the exterior of the connector housing62, may be the same or similar to known designs for MPO connectors.Indeed, these aspects are what partially define the associated opticalconnector 50 (FIG. 3 ) as being of the MPO-type. Thus, as is the casewith other connector housings of MPO-type optical connectors, theconnector housing 62 may also include a polarity key 68 on one side thatmust be aligned with a keyway in the adapter 60 to allow insertion intothe adapter 60. The polarity key 68 therefore orients the connectorhousing 62 relative to the adapter 60, and may also serve as a stopfeature to ultimately limit travel of the connector housing 62 in thedirection of insertion. Also like known MPO optical connectors, acoupling sleeve 72 may be provided on the connector housing 62 to assistwith coupling and uncoupling the connector housing 62 to/from theadapter 60. As is known, the coupling sleeve 72 is spring-biasedrelative to connector housing 62 to normally extend over the latchrecesses 66 (and the adapter latch arms, if they are engaged with thelatch recesses 66), but may be moved rearward relative to the connectorhousing 62 to no longer extend over the latch recesses 66, therebyreleasing the adapter latch arms to release the optical connector 50from the adapter 60. The connector housing 62 can be removed from theadapter 60 manually, i.e. without any tools (the coupling sleeve 72, ifpresent, is part of an assembly with the connector housing 62 and notconsidered to be a separate tool).

Normally a ferrule and a connector housing of an optical connector areassembled together during the process of terminating the optical fiberswith the optical connector. In other words, the final pre-terminatedassembly includes both the ferrule and the connector housing. And sincethese components are the minimum components required to define anoptical connector, the final pre-terminated assembly itself isconsidered to have an optical connector. This is not the case for theembodiment shown in FIG. 1 . The ferrule 52 (element for opticalalignment) is installed on optical fibers, but the connector housing 62(element for mechanical retention) is not. There is not yet an assemblyincluding the minimum attributes of an optical connector.

As shown in FIGS. 2 and 3 , the ferrule push 58 may be used to advancethe ferrule 52 into the connector housing 62 that has been pre-installedin the adapter 60. The ferrule 52 may be advanced until geometricfeatures on the connector housing 62 engage and retain a portion of theferrule push 58 in the end of the connector housing 62 that is outsidethe adapter 60. For example, the connector housing 62 may have featuresto engage ferrule push latches 74 that are provided on opposed sides ofthe ferrule push 58. By this point the ferrule 52 has been advanced suchthat the end face 54 protrudes slightly from the end of the connectorhousing 62 that is within the adapter 60 (note: an inner surface of theconnector housing 62 may be designed to confront a front-facing surfaceon a flange/shoulder 132 and thereby prevent the ferrule 52 from fallingout the end of the connector housing 62 during later use). With theferrule 52 now retained with the connector housing 62 by way of theferrule push 58 being coupled to the connector housing 62, the resultingassembly has the minimum attributes of an optical connector—an elementfor optical alignment (the ferrule 52) and an element for mechanicalretention (the connector housing 62 and its defined mechanical referencedatum(s)). In other words, an optical connector 50 can now be consideredas having been formed without ever removing the connector housing 62from the adapter 60. Simultaneously, installation of this opticalconnector 50 in the adapter 60 has been completed, as the opticalconnector 50 is ready for coupling with another MPO connector in theadapter 60.

The foregoing concept may be applied to any interconnect system thatinvolves a fiber optic cable, an optical connector intended to terminateat least one fiber of the fiber optic cable, and an adapter intended tocouple the optical connector to another optical connector. However, theconcept may be especially advantageous for interconnect systemsinvolving a large number of optical connections from a cable thatincludes a high fiber-count (e.g., 3,456 or more optical fibers), suchas the trunk cables in hyperscale data centers. Despite beingpre-terminated with some components of optical connectors according tothis disclosure, the size of such a trunk cable assembly can remainwithin acceptable limits for being pulled through ducts and intobuildings. Additionally, equipment to house the adapters 60 for theoptical connectors 50 can be comparable in size or smaller thanequipment used to store traditional optical connection to highfiber-count cables. As mentioned in the Background section above, thoseoptical connections are traditionally in the form of fusion splices.

By having an interconnect system that uses a pre-terminated cableinstead of one that requires splicing, the drawbacks associated withsplicing can be avoided. There is no longer a need for installers toundertake the time-consuming process of fusion splicing potentiallythousands of optical fibers to other optical fibers. Additionally,pre-terminated interconnect systems like the ones in this disclosure mayrequire less skill to install and therefore be less prone to operatorerror. The ferrule push 58 of the interconnect system may alsofacilitate the installation process in other ways, as will be describedin further detail.

To facilitate discussion and provide context, an exemplary environmentand use for high fiber-count cables will first be described below. Adescription of an example high fiber-count, pre-terminated cableassembly will then follow, before going into further detail on theferrule push 58 and related features that may be provided. Finally,example installation methods involving the high fiber-count,pre-terminated cable assembly will be discussed.

Example Environment (Data Center Cable Network)

As illustrated in FIG. 4 , a modern-day data center 10 may include acollection of buildings (referred to as a data center campus) having,for example, a main building 12 and one or more auxiliary buildings 14in close proximity to the main building 12. While three auxiliarybuildings are shown, there may be more or less depending on the size ofthe campus. The data center 10 provides for a local fiber optic network16 that interconnects the auxiliary buildings 14 with the main building12. The local fiber optic network 16 allows communication equipment 18in the main building 12 to communicate with various communicationequipment (not shown) in the auxiliary buildings 14. In the exemplaryembodiment shown, the local fiber optic network 16 includes trunk cables20 extending between the main building 12 and each of the auxiliarybuildings 14.

The trunk cables 20 may be similar to any of the cables described inInternational Patent Application Publication No. WO 2019/010291 A1 (“the'291 publication”), the disclosure of which is fully incorporated hereinby reference. Thus, although a brief description of one of the trunkcables 20 is provided below to introduce aspects related to thisdisclosure, reference can be made to the '291 publication for anunderstanding of other aspects and variations.

As illustrated in FIG. 5 , an example one of the trunk cables 20generally includes a high fiber-count arrangement of optical fibers 24(e.g., 3,456 or more optical fibers) for passing data and otherinformation through the local fiber optic network 16. The trunk cable 20includes a plurality of subunits 22, and each subunit 22 is configuredto carry a pre-selected number of optical fibers 24. Although the trunkcable 20 is shown as including twelve subunits 22, the number ofsubunits 22 may be more or less than this number in alternativeembodiments. The subunits 22 may be arranged within an outer protectivesheath 26 (also referred to as “outer cable jacket 26” or simply “cablejacket 26” or “outer jacket 26”), as is generally known in the industry.As mentioned above, each of the subunits 22 is configured to carry apre-selected number of optical fibers 24. By way of example and withoutlimitation, each subunit 22 may be configured to carry 144 or 288optical fibers 24. It should be recognized, however, that more or lessoptical fibers 24 may be carried by each of the subunits 22.

The optical fibers 24 in the subunits 22 may be arranged in differentgroups (i.e., distinct groupings, even though the groupings may have thesame number of optical fibers 24). As an example, the optical fibers 24may be configured as a plurality of optical fiber ribbons 28 (“ribbons28”). Alternative embodiments may include the optical fibers 24 in anon-ribbon form (e.g., “loose” optical fibers). Each ribbon 28 includesa plurality of the optical fibers 24 arranged in a generallyside-by-side manner (e.g., a linear array, as shown, or a rolled/foldedarray). Such ribbons are generally known and thus will not be describedfurther in this disclosure. Each ribbon 28 may include, for example,eight, twelve, sixteen, or any other number of the optical fibers 24.The ribbons 28 of a subunit 22 may be arranged within a subunit sheath30 (“subunit jacket 30”), which may be a thin layer of material that hasbeen extruded over the ribbons 28.

In the example illustrated in FIG. 4 , the trunk cables 20 from theauxiliary buildings 14 are routed to a distribution cabinet 32 (alsoreferred to as “distribution enclosure 32”) housed in the main building12. In alternative embodiments, there may be multiple distributioncabinets 32 in the main building for receiving the trunk cables 20.Thus, there may be one or more distribution cabinets 32.

Within the main building 12, a plurality of indoor fiber optic cables 34(“indoor cables 34”) are routed between the communication equipment 18and the one or more distribution cabinets 32. In an exemplary embodimentand as illustrated in FIG. 6 , each of the indoor cables 34 may beconfigured similar to the subunits 22, at least in terms of fiber countand fiber groupings, and thereby be configured to carry a pre-selectednumber of optical fibers 36. By way of example and without limitation,each indoor cable 34 may be configured to carry 144 or 288 of theoptical fibers 36. It should be recognized, however, that more or lessoptical fibers 36 may be carried by each of the indoor cables 34.

Similar to the optical fibers 24 of the subunits 22, the optical fibers36 in the indoor cables 34 may be configured as a plurality of opticalfiber ribbons 38 (“ribbons 38”). Thus, each ribbon 38 may include aplurality of optical fibers 36 arranged in a generally side-by-sidemanner (e.g., in a linear array or in a rolled/folded array). Again,such ribbons 38 are generally known in the industry and thus will not bedescribed further in this disclosure. Each ribbon 38 may include, forexample, eight, twelve, sixteen, or any other number of the opticalfibers 36. The ribbons 38 of an indoor cable 34 may be arranged withinan outer protective sheath 40 (also referred to as “cable outer jacket40” or simply “cable jacket 40”), as is generally known in the industry.

Although only the interior of the main building 12 is schematicallyshown in FIG. 4 and discussed above, each of the auxiliary buildings 14may house similar equipment for similar purposes. Thus, although notshown, each of the trunk cables 20 may be routed to one or moredistribution cabinets 32 in one of the auxiliary buildings 14 in amanner similar to that described above. Furthermore, each of theauxiliary buildings 14 may include indoor cables 34 that extend betweencommunication equipment 18 and the one or more distribution cabinets 32of the auxiliary building 14.

Example Pre-Terminated Cable Assembly

At least one end of at least one of the trunk cables 20 extendingbetween buildings 12, 14 may be pre-terminated in a manner consistentwith the introductory discussion in this Detail Description section.Thus, the optical fibers 24 of each ribbon 28 may be terminated by aferrule 52 in the manner described above with reference to FIGS. 1-3 .Each ribbon 28 may be terminated with a respective ferrule 52, such as12-fiber ribbons each being terminated with a respective 12-fiber MTferrule. Alternatively, groups of two or more ribbons 28 may beterminated with the same ferrule 52, such as groups of two 12-fiberribbons each being terminated with a respective 24-fiber MT ferrule.These terminations result in a pre-terminated trunk cable assembly(“pre-terminated trunk cable”) because they occur at the manufacturingsite of the pre-terminated trunk cable 80 rather than at the site ofintended use. Thus, the word “pre-terminated” is used in this disclosureto refer to terminations that take place by the manufacturer ofresulting cable assembly, prior to shipping to or deployment at a remotelocation/site of intended use (e.g., customer sites) (“the field”).

FIG. 7 schematically illustrates an end portion 82 of one of the trunkcables 20 pre-terminated with a plurality of the ferrules 52 to form apre-terminated trunk cable 80. Ferrule push components (e.g., ferrulepush 58) are not shown, but may be present as will be discussed below.The termination involves not only the installation of ferrules 52 andferrule push components, but also preparing the end portion 82 of thetrunk cable 20 for such installation. To this end, the pre-terminatedtrunk cable 80 includes a furcation body 84 associated with a first end86 of the cable jacket 26. For example, the furcation body 84 may beinstalled on the first end 86 such that the cable jacket 26 ends withinthe furcation body 84. The furcation body 84 represents a “breakout”,“branching”, or “fanout” point on the trunk cable, as end sections 88 ofthe subunits 22 extend from the furcation body 84 and beyond the firstend 86 of the cable jacket 26 so that the subunits 22 have more freedomto spread out. Various types of furcation bodies are known. In theembodiment shown, the furcation body 84 comprises a shell positioned onor near the first end 86 of the cable jacket 26 and polymer materialfilling the shell. The polymer material may be a cured adhesive, such asepoxy, so that the shell is secured to the cable jacket 26 and thesubunit jackets 30. In alternative embodiments, the furcation body 84may have a different construction and/or be secured to the trunk cable20 in a different manner.

In the embodiment shown in FIG. 7 , the end sections 88 of the subunits22 each include the associated subunit jacket 30 extending a certainlength from the furcation body 84, and the associated group of opticalfibers 24 extending a certain length from (i.e., beyond) the associatedsubunit jacket 30. For convenience, only a representative ribbon 28 andrepresentative ferrule 52 is schematically shown for each subunit 22 inFIG. 7 . A close-up of the representative ribbon 28 and representativeferrule 52 for two of the subunits 22 is schematically shown in FIG. 8 .As mentioned above, each subunit 22 may actually include a plurality ofribbons 28, such as twelve ribbons 28 that each have twelve opticalfibers 24 (144 fiber count per subunit 22), twenty-four ribbons 28 thateach have twelve optical fibers 24 (288 fiber count per subunit 22), orthe like.

Referring back to FIG. 7 , the end sections 88 of the subunits 22 aregrouped in pairs, with the end sections 88 of a given pair havingsubstantially the same length. For example, the lowermost pair in FIG. 7includes the subunit jackets 30 extending a length L1 from the furcationbody 84, and the optical fibers 24 extending a length L2 from thesubunit jacket 30. The total length of the end section 88 (i.e., L1+L2)may be referred to as the “leg length”. The different pairs of endsections 88 have different leg lengths to provide a staggeredarrangement of the ferrules 52. This staggering allows thepre-terminated trunk cable 80 to be placed within a smaller pullinggrip/sock (compared to if there were no staggering), and therefore, fitwithin smaller ducts or the like. These aspects will be described inconnection with example uses of the pre-terminated trunk cable 80further below.

In FIG. 7 , each successive group of end sections 88 has a leg lengththat is a distance D longer than the leg length of the preceding group.Thus, each group of end sections 88 is D longer than the previous groupsuch that there is substantially uniform (i.e., uniform or intended tobe uniform) staggering of the different groups of the ferrules 52. Inalternative embodiments, the staggering may be non-uniform. Thedifferent leg lengths may be due to the subunit jackets 30 extendingfurther from the furcation body 84. Thus, the length L2 that the opticalfibers 24 extend beyond the corresponding subunit jacket 30 may remainsubstantially the same (i.e., the same or intended to be the same). Aconsistent length of exposed ribbons 28 may allow consistent processingby the manufacturer of the pre-terminated trunk cable 80 whenterminating the optical fibers 24. In other words, termination processesmay be based on a certain exposed length of each ribbon 28 (e.g., forfixtures, stripping equipment, etc.). When that length is provided, thetermination processes may be performed in a repeatable manner.Alternative embodiments without consistent lengths of exposed ribbons 28are nevertheless within the scope of this disclosure as well.

In addition to being pre-terminated with the ferrules 52, the trunkcable 20 may be pre-terminated with a plurality of the ferrule pushcomponents 58 (FIGS. 1-3 ) described above. FIGS. 7 and 8 do notillustrate the ferrule push components 58 and other, optional componentsto simplify the drawings. Instead, reference can be made to FIGS. 9-11 ,which illustrate a representative termination. In FIG. 9 , two ribbons28 are shown as being terminated by a ferrule 52 in the form of a24-fiber, MT ferrule. Only a short length of each ribbon 28 is shown forconvenience; to ease understanding of other components shown in thedrawings. It will be appreciated that the ribbons 28 extend rearwardlyfrom the ferrule 52 and the ferrule push component 58, and ultimatelyinto a subunit jacket 30, as schematically shown in FIG. 7 and discussedabove. A ferrule boot 94 received in a rear portion of the ferrule 52supports the optical fibers 24 as they extend from the ferrule 52.Because the termination of optical fibers with ferrules and the use offerrule boots are generally known, these aspects will not be describedin further detail.

FIG. 9 also illustrates a guide pin assembly 96 behind the ferrule 52.The guide pin assembly 96 includes the guide pins 56 secured to a pinkeeper 98. The guide pins 56 are intended to extend through pin holes100 in the ferrule and project beyond the end face 54, while the pinkeeper 98 is intended to rest against a back surface of the ferrule 52and prevent the guide pins 56 from being removed. It may be possible,however, to actuate the pin keeper 98 (e.g., by squeezing or expandingtabs) to allow intentional removal of the guide pins 56 from the frontof the ferrule 52. Like the ferrule 52 and the ferrule boot 94, the useof guide pin assemblies is generally known such that this aspect willalso not be described in further detail. Indeed, the guide pin assembly96 is an optional component in any event.

More pertinent to this disclosure is the ferrule push 58 shown in FIG. 9and an optional dust cap 110. The ferrule push 58 is a generallyelongate structure with a front end 112, a back end 114, and an internalcavity 116 extending between the front end 112 and the back end 114. Theinternal cavity 116 allows the ferrule push 58 to be received over theribbons 28, which may be done prior to terminating the ribbons 28 withthe ferrule 52. The ferrule push 58 in the embodiment shown is designedto be installed on the ribbons 28 in a particular orientation.Specifically, one side of the ferrule push includes a polarity key 118intended to be oriented on a particular side of the ribbons 28. Theribbons 28 are considered to have sides in the sense that the opticalfibers 24 have a predefined order. Individual optical fibers 24 of aribbon 28 have different colors, and the colors are arranged in apre-defined order that is well-known in the telecommunications industry.Reference can be made to textbooks or standards like TIA/EIA 598-B:2001, for example. The first optical fiber 24 of a ribbon 28 has a bluecolor, while the twelfth optical fiber 24 has an aqua color. On one sideof the ribbon 28 the optical fibers 24 will appear in the normal orderof 1 to 12 (blue to aqua), while on the other side of the ribbon 28 theoptical fibers 24 will appear in reverse order, i.e. 12 to 1 (aqua toblue).

Advantageously, the ferrule push 58 includes slots or openings 120 onopposed sides to provide visibility into the internal cavity 116. Theopenings 120 allow at least the first and last optical fibers 24 in theribbons 28 to be seen by a technician. Thus, when placing the ferrulepush 58 on the ribbons 28, the technician can verify that the polaritykey 118 is on the desired side of the ribbons 28 (i.e., the sidecorresponding to the normal order or reverse order of the optical fibers24, whichever is desired). Additionally, a window (not shown) on the topor bottom of the ferrule push 58 may be provided to view the correctorder of the optical fibers 24. The polarity key 118 not only orientsthe ferrule push 58 relative to the ribbons 28, but also serves toorient the ferrule push 58 relative to the connector housing 62 whenforming the optical connector 50. Referring back to FIGS. 1-3 , it canbe seen how the connector housing 62 includes an internal keyway 70 onone surface so that the ferrule push 58 can only be inserted into theconnector housing 62 in a single orientation. Thus, ultimately, theribbons 28 are oriented relative to the adapter 60.

As shown in FIG. 9 , the openings 120 on the sides of the ferrule push58 are spaced from the front end 112. A front portion 124 of the ferrulepush 58 extending front the front end 112 to the openings 120 is shapedto receive the ferrule boot 94 in the internal cavity 116. As shown inFIG. 10 , after terminating the optical fibers 24 with the ferrule 52,the ferrule push 58 may be pushed forward against the back of theferrule 52. This may occur after pushing the pin keeper 98 against theback of the ferrule 52, or the latter may occur simultaneously. That is,the ferrule push 58 may be used to push the pin keeper 98 against theback of the ferrule 52. Either approach results in the guide pins 56being pushed through the pin holes 100 in the ferrule 52 until portionsof the guide pins 56 project beyond the end face 54. In the embodimentshown, the ferrule push 58 includes front stops 126 (or “bumpers 126”)that extend past the pin keeper 98 to directly contact the back of theferrule 52. Thus, although the pin keeper 98 may be sandwiched betweenthe ferrule 52 and the ferrule push 58, there is still at least somedirect contact between the ferrule 52 and the ferrule push 58. Thepresence of the front stops 126 ensures that the ferrule push 58 stillregisters to the back of the ferrule 52 regardless of whether a guidepin assembly 96 is present or absent (as is the case for femaleconfigurations of the ferrule 52). The ferrule push 58 in the embodimentshown also includes guide pin slots 128 on the sides of the frontportion 124 to accommodate portions of the guide pins 56 located behindthe pin keeper 98.

Unlike a connector housing, the ferrule push 58 does not extend past ashoulder/flange 132 on the ferrule 52 that defines or is proximate tothe back of the ferrule 52. The ferrule push 58 does not extend over theferrule 52 at all in some embodiments, with the front stops 126 simplycontacting the back of the ferrule 52. Indeed, another advantage of thedesign in the embodiment shown is that the ferrule push 58 may have thesame or substantially the same cross-sectional footprint as the ferrule52. The term “footprint” as used in this disclosure refers to onlyheight, only width, or both height and width of the component inquestion (e.g., the ferrule 52 and/or the ferrule push 58) when viewedin a cross-sectional plane that is perpendicular to a longitudinal axisof the component. FIG. 10 illustrates how the front portion 124 of theferrule push 58 has a footprint that generally matches the back of theferrule 52. The polarity key 118 on the top of the ferrule push 58,along with the rear flanges 130 on sides of the ferrule push 58, mayprotrude no further than or only slightly further than the footprintdefined by the shoulder/flange 132 of the ferrule 52. By having afootprint that is substantially the same or less than that of theferrule 52, the ferrule push 58 may be installed on the ribbons 28 ofthe trunk cable 20 without increasing (or at least without substantiallyincreasing) the footprint beyond increases resulting from installationof the ferrules 52. As a specific example, the ferrule push 58 may havea maximum height and maximum width that is less than 20%, less than 15%,or even less than 10%, larger than the maximum height and maximum widthof the ferrule 52, when viewed in cross-sectional plane perpendicular toa longitudinal axis of the ferrule 52. While the length of the ferrulepush 58 is shown larger than a length of the ferrule 52, this is not arequirement, as the ferrule push 58 may have the same length or asmaller length than the ferrule 52.

The ferrule 52, the pin keeper 98 (if present), and the ferrule push 58may be secured together using an adhesive. Alternatively oradditionally, the dust cap 110 may be used to retain the componentstogether. The dust cap 110 has an interior space 140 that accommodatesthe ferrule 52, the guide pin assembly 96 (including the portions of theguide pins 56 that project from the end face 54), the front portion 124of the ferrule push 58, and an adjacent portion of the ferrule push 58that includes the openings 120 and the polarity key 118. Thus, as shownin FIGS. 10 and 11 , the ferrule push 58, the guide pin assembly 96, andthe aforementioned portions of the ferrule push 58 may be inserted intothe dust cap 110. Or, stated differently, the dust cap 110 may bereceived over the ferrule 52, the guide pin assembly 96, and theaforementioned portions of the ferrule push 58. In the embodiment shown,the ferrule push latches 74 reside in cutouts 144 on opposed sides ofthe dust cap 110 when the dust cap 110 is installed. Thus, in theembodiment shown, the dust cap 110 does not contact or cover the ferrulepush latches 74.

To accommodate the polarity key 118 without a substantial increase infootprint, a top surface of the dust cap 110 includes a window 150 inwhich the polarity key 118 resides when the dust cap 110 is installed.The portion of the dust cap 110 adjacent (and defining) a back edge ofthe window 150 may be considered as a crossbar 152, and may includefeatures to assist with travel over the polarity key 118 duringinstallation of the dust cap 110. For example, as shown in FIG. 11A, thecrossbar 152 may include a ramped or inclined surface 154 facing theinterior of the dust cap 110 (note: FIG. 11A is merely schematic, withstructural details within some elements omitted or simplified). Thepolarity key 118 may also include features to assist with the dust cap110 traveling over the polarity key 118 during removal of the dust cap110. For example, as shown in FIG. 11A a rearward-facing surface 156 ofthe polarity key 118 may be ramped or inclined to make it easier for aforward-facing surface of the crossbar 152 to slide back over thepolarity key 118. It will be appreciated that this embodiment is merelyan example, and that other embodiments may not include features on thedust cap 110 and/or the polarity key 118 to assist with travel of thedust cap 110 over the polarity key 118.

Referring back to FIG. 10 , a window 150 may also be provided on abottom surface of the dust cap 110 so that the dust cap 110 can beinstalled in different orientations. It therefore does not matterwhether the top surface or the bottom surface is aligned with thepolarity key 118 when installing the dust cap 110. The discussion aboveabout features to assist with the dust cap 110 sliding over the polaritykey 118 apply equally to the bottom surface, which may have the samefeatures as the top surface.

As can be seen in FIGS. 10 and 11 , the dust cap 110 may have a lowprofile; one that does not substantially increase the cross-sectionalfootprint of a sub-assembly 168 that comprises the ferrule 52 and theferrule push 58. For example, in some embodiments, the dust cap 110 mayhave a maximum height and maximum width that is less than 15%, or evenless than 10%, larger than the maximum height and maximum width of theferrule 52, when viewed in cross-sectional plane perpendicular to alongitudinal axis of the ferrule 52. By having a footprint that is onlyslightly larger than the ferrule 52, a dust cap 110 may be installed oneach of the ferrules 52 of the pre-terminated trunk cable 80 (FIG. 7 )without substantially increasing the overall footprint of thepre-terminated trunk cable 80. This may allow the pre-terminated trunkcable to still fit within a desired sized of a pulling grip (and,therefore, desired sizes of ducts for the pulling grip). Thus, the dustcaps 110 may be used not only to protect the ferrules 52 from dust,debris, and other contaminants in a conventional manner (e.g., duringstorage), but also to provide mechanical protection within a pullinggrip during installation, when the ferrules 52 might otherwise besubject to scratches or the like (e.g., from contacting other ferrulesor portions of the pulling grip) when being pulled through ducts.Additionally, as mentioned above, the dust cap 110 may assist in keepingthe ferrule 52, the guide pin assembly 96, and the ferrule push 58assembled together (as the sub-assembly 168), instead of or in additionto using adhesive, tape, or some other means of retaining the componentstogether.

FIG. 12 illustrates the pre-terminated trunk cable 80 on a reel 170 andan example of a pulling grip assembly 172 (also referred to as “pullinggrip 172” or “pulling sock 170”) installed over an end portion of thepre-terminated trunk cable 80 (e.g., the end portion 82 represented inFIG. 7 ). The pulling grip 172 covers all of the ferrules 52, theferrule push components 58, and the dust caps 110 associated with theend portion 82. It has already been mentioned how the staggering of theferrules 52, the design of the ferrule push components 58, and thedesign of the dust caps 110 can help minimize the footprint of thepulling grip 172. For a given pulling grip design, the maximumwidth/diameter can be less than what it would need to be to accommodatethe trunk cable 20 being pre-terminated with assemblies considered to beoptical connectors. Additional details of the pulling grip 172 need notbe discussed for the purpose of this disclosure. FIG. 12 is merelyprovided for context to show how the pre-terminated trunk cable 80 maybe delivered to an intended site of installation, such as the datacenter 10 (FIG. 3 ). At the site of installation, the pre-terminatedtrunk cable 80 is ultimately installed and used as part of aninterconnect system. An example installation of such an interconnectsystem for the data center 10 will now be described.

Example Installation and Interconnect System

FIG. 13 illustrates one possible embodiment for the distributioncabinets 32 mentioned above in connection with FIG. 4 . The distributioncabinet 32 may be similar to embodiments described in PCT PatentApplication Publication Nos. WO 2019/079460 A1 (“the '460 publication”)and WO 2019/079425 A1 (“the '425 publication”), the disclosures of whichof fully incorporated herein by reference. Indeed, the FIG. 13 generallycorresponds to FIG. 1 of the '425 publication such that reference can bemade to the '425 publication for a more complete understanding ofaspects not discussed below. Only a brief overview is provided belowbefore focusing on differences from the '425 publication that arespecific to this disclosure.

As shown in FIG. 13 , the distribution cabinet 32 includes various wallsthat are assembled together to define an interior volume 178. Inparticular, the distribution cabinet 32 includes a rear wall 180, afirst side wall 182 and a second side wall 184 coupled to opposite sidesof the rear wall 180, and a lower wall 186 and an upper wall 188respectively coupled to a top and bottom of each of the rear wall 180,the first side wall 182, and the second side wall 184. A front door 190is pivotally coupled to the first side wall 182 (e.g., by hinges 192) toprovide selective access to the interior volume 178. The distributioncabinet 32 also includes a tray assembly 194 within the interior volume178 that comprises a tray housing 196 pivotally coupled to thedistribution cabinet 32 and a plurality of trays 198 coupled to the trayhousing 196. The tray housing 196 may pivot/rotate outward from theinterior volume 178 to facilitate access to the trays 198. The trays 198themselves may pivot or otherwise move relative to the tray housing 196(including being removable from the tray housing 196) to provideadditional access to any given tray 198.

The '425 publication refers to the trays 198 as “splice trays” becausethey are intended to store fusion splice joints between the opticalfibers of two different cables. Because the present disclosure relatesto pre-terminated cables rather than ones that require splicing, themore generic term “tray” is used. The trays 198 are still intended tostore joints between the optical fibers of two different cables, but thejoints are in the form optical connectors mated (i.e., coupled) togetherusing respective adapters. The trays 198 may therefore be referred to as“adapter trays 198” or “patch trays 198” and the distribution cabinet 32as a “patch cabinet 32” or “patch enclosure 32”.

FIG. 14 illustrates a possible embodiment for a representative one ofthe trays 198. As shown in FIG. 14 , the tray 198 includes a series orbank of the adapters 60 coupled to the tray 198. Any common grouping andmounting of adapters may be considered as an adapter panel for thepurpose of this disclosure. In the embodiment of FIG. 14 , the adapters60 are commonly mounted in a support 202 that, in turn, is mounted tothe tray 198. The support 202 with the adapters 60 may be considered asan adapter panel, or more generally the tray 198 assembled with theadapters 60 may be considered as an adapter panel. Indeed, inalternative embodiments, the adapters 60 may be mounted to the tray 198individually instead of by way of a common support. Embodiments of“ganged” adapters mounted to the tray 198 are also possible. Each of theadapters 60 includes a respective connector housing 62 pre-installed onone side, as discussed above in connection with FIGS. 1-3 , therebyforming respective adapter assemblies 64 that are pre-populated withrespective connector housings 62 that are not intended to be removed.

Now referring collectively to FIGS. 4 and 12-14 , the pre-terminatedtrunk cable 80 may be routed from one building (main building 12 orauxiliary building 14) to another in the data center 10. This mayinvolve using the pulling grip 172 to pull the pre-terminated trunkcable 80 through ducts that extend into and out of the buildings, andpossibly between the buildings. Ultimately the end portion 82 thatincludes the pulling grip 172 may be routed into the interior volume 178of the distribution cabinet 32. Various features may be provided in thedistribution cabinet 32 to assist with receiving the pre-terminatedtrunk cable 80. Although FIG. 13 illustrates a transparent rear plate210 without openings as a rear portion of the upper wall 188, such aplate may include different sized openings for different types ofcables. For example, there may be openings sized to receive the larger,high fiber-count pre-terminated trunk cables 80, and openings sized toreceive the relative smaller fiber-count indoor cables 34. A front plate212 defining a front portion of the upper wall 188 may also be removableto assist with accessing the pre-terminated trunk cable 80 and othercables as they are routed into the distribution cabinet 32 (e.g.,through the openings in the rear plate 210, if present). Additionally,the distribution cabinet 32 may include brackets 216 below the rearplate 210 that serve as mounting locations for the pre-terminated trunkcable 80 and other cables. Apertures 218 or other mounting features maybe provided on the brackets 216 for cooperating with complementarymounting features of clips (not shown), which may be integral with thecables (e.g., part of the furcation body 84) or mounted to the cables.

Ultimately the pulling grip 172 is removed from the pre-terminated trunkcable 80 to expose the end sections 88 (FIG. 5 ) of the subunits 22.This may be done before or after securing the pre-terminated trunk cable80 to the brackets 216. Regardless, having routed the end portion 82into the distribution cabinet 32 using the pulling grip 172, the endsections 88 of the subunits 22 are positioned close the trays 198. Thismay help minimize the amount of further routing or handling of thepre-terminated trunk cable 80 after the pulling grip 172 is removed,thereby reducing the potential for damage that results from sections ofthe ribbons 28 now being exposed (the end portions of the optical fibers24 that extend from the associated subunit jackets 26).

The connection of each subunit 22 of the pre-terminated trunk cable 80to the corresponding indoor cable 34 generally takes place in acorresponding one of the trays 198. For example, FIG. 14 may representthe tray 198 associated with the connection between one of the subunits22 and a corresponding indoor cable 34. When it is desired to make thatconnection, the tray 198 is accessed from the tray assembly 194. Boththe pre-terminated sub-assemblies 84 of the subunit 22 (thesub-assemblies that each comprise one or more ribbons 28 having aferrule 52 and a ferrule push 58) and the adapters 60 are then preparedfor coupling. For each pre-terminated sub-assembly 84, this involvesremoving the dust cap 110 from the ferrule 52 and the ferrule push 58.As shown in FIGS. 15 and 16 , there may be a dust cover 220 (sometimesreferred as “dust plug”) that has been pre-installed in thecorresponding connector housing 62. This may be done at the time ofassembling the connector housing 62 with the adapter 60 to prevent dust,debris, and other sources of contamination from entering the connectorhousing 62 and the adapter 60 prior to use. Like conventional dust plugsfor adapters, the dust cover 220 may simply be removed by pulling it outof the component in which it is received (the connector housing 62 inthe case of the dust cover 220), as shown in FIG. 16 .

Once the dust cap 110 and the dust cover 220 have been removed from thepre-terminated sub-assembly 84 and the associated adapter assembly 64,the ferrule push 58 may be used to insert the ferrule 52 into theconnector housing 62. As mentioned above in connection with FIGS. 1-3 ,the ferrule 52 may be advanced until its end face 54 protrudes slightlyfrom the end of the connector housing 62 within the adapter 60.Geometric features within the connector housing 62 ultimately limittravel of the ferrule 52 in the direction of insertion. The connectorhousing 62 may also engage and retain a portion of the ferrule push 58in the end of the connector housing 62 that is outside the adapter 60.With the ferrule 52 now retained with the connector housing 62, theresulting assembly has the minimum attributes of an optical connector—anelement for optical alignment (the ferrule 52) and an element formechanical retention (the connector housing 62 and its mechanicalreference datum(s)). In other words, the optical connector 50 can now beconsidered as having been formed. At the same time, installation of thisoptical connector 50 in the adapter 60 is complete, as the opticalconnector 50 is ready for coupling with another MPO connector in theadapter 60.

The process described above may be repeated for each of thepre-terminated sub-assemblies 84 associated with the subunit 22 and thecorresponding adapter assemblies 64 on the tray 198. Connections to thecorresponding indoor cable 34 may be done at the same time (e.g., if theindoor cable 34 is already coupled to the adapters 60) or later. Inother words, the order of these steps may vary. A subunit 22 of thepre-terminated trunk cable 80 may be coupled to the adapters 60 of thecorresponding tray 198 prior to the corresponding indoor cable 34 beingcoupled to the adapters 60, or vice-versa.

Regardless of the timing, the indoor cable 34 may be routed into thedistribution cabinet 32 in a manner similar to the pre-terminated trunkcable 80. Before or after securing the indoor cable 34 to thedistribution cabinet 32, optical connectors (not shown) that have beenpre-installed on the indoor cable 34 are coupled to the correspondingadapters 60 on the tray 198. The adapters 60 may each have a dust cover220 pre-installed on the side intended to receive the optical connectorsof the indoor cable 34. Thus, if present, the dust covers 220 areremoved prior to coupling the optical connectors to the correspondingadapters 60.

Once the optical connectors associated with the subunit 22 have beenformed (simultaneously with completing their installation in theadapters 60) and the optical connectors of the indoor cable 34 have beencoupled to the adapters 60, optical connections between the subunit 22and the indoor cable 34 have been established. The adapters 60 align andhold the optical connectors together to allow light to travel betweenthe optical fibers 24 of the subunit 22 and the optical fibers 36 of theindoor cable 34. The tray 198 including the adapters 60 may then bemoved back to a storage position in the tray housing 196, and theprocess repeated for a different subunit 22, tray 198, and indoor cable34.

The are many alternatives and variations that will be appreciated bypersons skilled in optical connectivity without departing from thespirit or scope of this disclosure. For example, as mentioned above, anycommon grouping and mounting of adapters may be considered as an adapterpanel for the purpose of this disclosure. Adapter panels may includeadapters arranged in a plurality of adapter rows, a plurality of adaptercolumns, or both a plurality of adapter rows and a plurality of adaptercolumns. To this end, in some embodiments, the adapter panels may belocated in frames or support members other than trays. Also, in someembodiments, each row of the plurality of adapter rows or each column ofthe plurality of adapter columns includes a sufficient number of theadapters 60 to correspond to the ferrules 52 associated with any of thesubunits 22.

For at least this reason, the invention should be construed to includeeverything within the scope of the appended claims.

What is claimed is:
 1. A method of forming an interconnect system,comprising: (a) installing a plurality of ferrules and a plurality offerrule push components that correspond to the plurality of ferrules ona cable that includes different groups of optical fibers, wherein eachferrule of the plurality of ferrules terminates one or more respectivegroups of the different groups of optical fibers, and wherein eachferrule push component of the plurality of ferrule push components isinstalled on the one or more respective groups of the optical fibersthat are terminated by the corresponding ferrule; and (b) installing aplurality of connector housings in a plurality of adapters of at leastone adapter panel, wherein the plurality of connector housings areconfigured to receive and retain the plurality of ferrules and theplurality of ferrule push components without being removed from theplurality of adapters.
 2. The method of claim 1, wherein step (a)results in a pre-terminated cable assembly, the method furthercomprising: installing a pulling grip assembly on an end of the cableand over the plurality of ferrules and the plurality of ferrule pushcomponents, wherein the plurality of connector housings remain installedin the plurality of adapters so as to not be part of the pre-terminatedcable assembly when installing the pulling grip assembly.
 3. The methodof claim 2, wherein the at least one adapter panel is included in acabinet, the method further comprising: shipping the pre-terminatedcable assembly and the cabinet as independent assemblies to a remotesite.
 4. The method of claim 3, further comprising: routing the pullinggrip assembly toward the at least one adapter panel; removing thepulling grip assembly after the routing to expose the plurality offerrules; and installing the plurality of ferrules in the plurality ofadapters by inserting the plurality of ferrule push components into theplurality of connector housings.
 5. The method of claim 4, wherein thestep of installing the plurality of ferrules in the plurality ofadapters results in the plurality of ferrules and the plurality ofconnector housings being coupled together to define a correspondingplurality of optical connectors that are installed in the plurality ofadapters.
 6. The method of claim 5, wherein: the step of installing theplurality of ferrules in the plurality of adapters is performed withoutany tools; and once the step of installing the plurality of ferrules inthe plurality of adapters is complete, the plurality of opticalconnectors are removable from the plurality of adapters without anytools.
 7. The method of claim 4, wherein the routing step furthercomprises: routing the pulling grip assembly through a duct and throughan opening in the cabinet; and thereafter removing the pulling gripassembly to expose the plurality of ferrules and the plurality offerrule push components.
 8. The method of claim 7, wherein the pullinggrip assembly is removed from the end of the pre-terminated cableassembly without a tool.
 9. The method of claim 4, further comprising:moving the at least one adapter panel from an installed position in aninterior volume of the cabinet to a position at least partially outsidethe interior volume; wherein for each adapter panel of the at least oneadapter panel, the step of installing the plurality of ferrules in theplurality of adapters is performed when the adapter panel is theposition at least partially outside the interior volume.
 10. The methodof claim 1, wherein step (a) results in a pre-terminated cable assembly,the method further comprising: (c) routing an end of the pre-terminatedcable assembly that includes the plurality of ferrules from a remotelocation toward the at least one adapter panel; and (d) installing theplurality of ferrules in the plurality of adapters by inserting theplurality of ferrule push components into the plurality of connectorhousings, wherein the plurality of connector housings are coupled to theplurality of adapters before the installing step and remain coupled tothe plurality of adapters during the installing step.
 11. The method ofclaim 10, wherein step (d) results in the plurality of ferrules and theplurality of connector housings being coupled together to define acorresponding plurality of optical connectors that are installed in theplurality of adapters.
 12. The method of claim 11, wherein step (d) isperformed without any tools.
 13. The method of claim 12, wherein: step(d) results in the plurality of ferrules and the plurality of connectorhousings being coupled together to define a corresponding plurality ofoptical connectors that are installed in the plurality of adapters; andonce step (d) is complete, the plurality of optical connectors areremovable from the plurality of adapters without any tools.
 14. Themethod of claim 1, further comprising: installing a plurality of dustcovers in the plurality of connector housings, wherein each dust coverof the plurality of dust covers is received in an end of a correspondingconnector housing of the plurality of connector housings, the end beingoutside the adapter in which the corresponding connector housing isinstalled.
 15. The method of claim 1, wherein step (a) results in apre-terminated cable assembly, and wherein the at least one adapterpanel is included in a cabinet, the method further comprising: shippingthe pre-terminated cable assembly and the cabinet as independentassemblies to a remote site.
 16. The method of claim 15, wherein an endof the pre-terminated cable assembly that includes the pluralityferrules does not include optical connectors during the shipping step.17. The method of claim 1, wherein the plurality of connector housingsand the plurality of ferrule push components are shaped so that eachconnector housing is only configured to receive each ferrule push in asingle orientation of the ferrule push relative to the connectorhousing.
 18. The method of claim 1, wherein each ferrule of theplurality of ferrules terminates a single group of the different groupsof optical fibers.
 19. The method of claim 1, wherein each ferrule ofthe plurality of ferrules terminates multiple groups of the differentgroups of optical fibers.
 20. The method of claim 1, wherein: eachferrule of the plurality of ferrules includes a front end that definesan end face where the respective one or more groups of the differentgroups of optical fibers terminate, a back end opposite the front end,and a shoulder between the front end and the back end that defines amaximum height and a maximum width of the ferrule in a cross-sectionalplane perpendicular to a longitudinal axis of the ferrule; and eachferrule push component of the plurality of ferrule push components has amaximum height and maximum width in a cross-sectional planeperpendicular to a longitudinal axis of the ferrule push that issubstantially the same or less than the maximum height and maximum widthof the corresponding ferrule.